Generally, in an imaging device of a digital camera or the like, image processing such as color interpolation processing is performed on RAW image data output from an imaging sensor, and data after the image processing are compressed in a general image file format. For example, in shooting of a still image, data after image processing are compressed in a JPEG (Joint Photographic Experts Group) format. Further, in shooting of a moving image, data after image processing are compressed in an MPEG (Moving Picture Experts Group) format or the like. Data after compression are stored in a storage medium or the like.
In recent years, digital cameras which store RAW image data at a time of shooting a still image in a storage medium or the like are becoming popular. The RAW image data are utilized when, for example, a color tone, a contrast, or the like of an image is adjusted accurately after shooting. Note that in the RAW image data, generally, the data amount is large as compared to data on which image processing and compression processing are performed. Accordingly, there has been proposed a technique to compress RAW image data at a time of shooting a still image by each of color components, and store data after compression of each of the color components in a storage medium or the like (for example, refer to Patent Document 1).    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-125241